Battery separator



c. F. HAUNZ v BATTERY SEPARATOR May 14 1935.

Filed July 21, 1953 Patented May 14;;

UNITED STATES PATENT v OFFICE 12 Claims.

This invention relates to storage batteries, and particularly to the insulating separators or partivery large storage cells of submarine boats and power stations. due to the fact that wood has ideal physical characteristics and porosity. The wood separators are gradually pulpifled or disintegrated in the acid electrolyte, and particularly so on the side or face thereof which is in direct contact with the positive plate or electrode.

When a storage battery is being charged, acid is exuded from the active materials of the plate,

mechanically to the deterioration of the wood separators. The small voidsin the faces of a separator are receptive to minute particles of peroxide and sulphate, which gradually fill up thepores or voids and causeanincrease of volume and of the internal lesistance of the separator.

An object of this invention is to provide an improved wood separator for storage batteries which will eliminate or decrease the immediate contact between the peroxide of the wood;

a and which will prevent or minimize the invasion of solid particles into the structure of the wood.

- Another object of the invention is to provide Various other objects and advantages will be apparent from the following description of an embodiment of the invention, and the novel features will be particularly pointed out hereinafter in connection with the appended claims.

In the accompanying drawing:

Fig. 1 is a sectional plan, on an enlarged scale, of a portion of a. storage battery having wood separators constructed in accordance with this invention. 10"

.. Fig. 2 is an enlarged sectional plan of a portion of one of the separators; and Fig. 3 is a sectional plan of a portion of a separator, and illustrating the application of the invention to a slightly difierent'type of separator. In the illustrated embodiment of the invention I provide within the usual or any suitable battery casing III, a plurality of pos tive plates or electrodes II and a plurality of neg tive plates or electrodes l2, the positive and negative plates or electrodes being arranged side by side alternately. Wood separators l3 are interposed between adjacent plates II and I2, and these wood separators are provided with vertically extending grooves II in one or both faces thereof, and es- 25 pecially in the face abutting the positive plate. The face of each separator which abuts the negativeplate is usually and preferably made rather rough so that the electrolyte may easily reach all portions of the surface or face of the negative plate.- The grooves- M are separated by ribs ll which are usually of lesser width than the grooves. This isthe conventional or common type of stor- I age battery, and this invention relates to :the

. preliminary treatment of the wood separator 13. In accordance with this invention, I provide a suitable protective coating it upon the crest faces of the ribs l5,'or the improved portions of the face of each separator, and this coating is one which not interfere with the chemical action normally occurring in-the battery while the battery is being charged or discharged. This coating may be of various materials that are chemically inert in the battery, but is preferably a metallic coating, and I have found that metallic lead and antimony are both particularly satisfactory as the coating material. I have also discovered that a mixture of metallic lead and antimony may be advantageously employed, a mixture of ninety parts of lead and ten parts of antimony iving excellent results. The coating should be relatively thin, and I have found that a coating having an approximate thickness of from two to four thousandths of an inch is very satisfactory. The surfaces of the separators within the grooves are not treated and, therefore, the acid may pass from face to face of each separator through the pores-of the grooved portions thereof, and the insulating property of the separator is not destr y d.

'Ihefinetallic coating is preferably applied to A machine which may be satisfactorily employed for impregnating the surface ofthe wood .or impregnatin of a storage battery is their conductivity with molten metal is described and claimed in my prior, copending application, Ser. No. 586,861, filed January 15, 1932. In accordance with the disclosure of that application, molten metal is forced under pressure against the face area of a body of wood to be coated and the molten metal penetrates the pores of the wood and adheres thereto. The depth of penetration can be controlled by varying the pressure exerted on the molten metal, the temperature of the metal, and the duration of contact, but obviously other means for coating wood with metal may be employed, if desired, within the broader concept of the invention.

In Fig. 3 I have illustrated the separator as having grooves ll upon both faces thereof, so as to have ribs that abut against both positive and negative plates, and the crest faces of the ribs upon both sides or faces of the separator are impregnated or coated with the molten metal inthe same manner.

The metallic coating upon the crest faces of the ribs does not destroy the insulating property of the separator, nor materially interfere with the free flow mf the electrolyte from face to face through the separator, because this flow normally occurs through the thin part of the separator which is at the bottoms of the grooves or between the ribs. The metallic coating on the ribs effectively protects the wood from deterioration due.

to the action of the acid and the nascent oxygen which is libe ted at the positive plates during the chargin zperation and, therefore, the life having separators treated in this manner is very greatly increased, yet the treated separators are not materially thicker, not

impaired, but rather en- The positive electrode is in direct contact with the wood separator. The action of the strong acid, in combination with the nascent oxygen liberated in the battery, breaks down the cellulose content of the wood, forming organicacids. principally acetic acid. Such acids'have deleterious effects on the active materials of the plates, and cause loss of e'ficiency.

It will be obvious that various changesin the details and materials, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed claims.

I claim as my invention:

1. A' separator forstorage batteries, comprising a thin board of wood having portions only of thereof, the crest faces of said ribs in the appended a face thereof coated with a metallic substance.

2. A separator for storage batteries comprising a thin board ofwood having grooves in a face thereof, the ungrooved portions of said face having a metallic protecting coating and the grooved portions being free of said coating.

3. A separator for storage batteries comprising a thin board of wood having grooves in a face thereof, the ungrooved portions of said face bein impregnated to a slight depth with a metallic substance, and the grooved portions being free of said impregnation.

4. A separator for storage batteries, comprising a thin board of wood having spaced ribs on opposite faces thereof, the crest faces of said ribs being impregnated to a slight depth with a metallic substance, and the other faces of the ribs being free of saidimpregnation.

5. A separator for storage batteries comprising athin board of wood having ribs on a face thereof, the crest faces of said ribs being impregnated with a thin layer of a metallic substance, the portions of said board between said ribs being free of said layer.

6. A'separator for storage batteries comprising a thin board of wood having ribs on a face being impregnated to a small depth with a metallicsubstance containing lead and antimony, and the remainder of said board being free of .said substance.

I. A separator for storage batteries comprising a thin board of wood having ribs on a face thereof, the crest faces of said ribs being impregnated to a small depth with a metallic substance containing lead 'and antimony in the proportion of ninety parts of lead and ten parts of antimony, and the portions between the ribs being fnee of such impregnation.

8. A separator for storage batteries comprising a thin board of wood having ribs on a face thereof, the crest faces of said ribs being impregnated to a depth of approximately .002 to .004 inch with a metallic substance, and the portions between the ribs being free of such impregnation.

9. A separator forstorage batteries comprising a thin board of wood having ribs on a face thereof, the crest faces of said ribs being impregnated to a, slight depth' with a protecting substance containing metallic lead, and the portion of the board between the ribs being free of said substance.

10. A separator for storage batteries comprising a thin board of wood havin ribs on a face thereof, the crest pregnated to a slight containing metallic antimony. of the board between the ribs substance.

11. A separator for storage batteries comprising a thin board'of wood having ribs on a' face thereof, the crest faces of said ribs having a surface coating of metallic lead and antimony, and the portion of the board between the ribs being free of said coating.

12. A separator for storage batteries comprising 'a thin board of wood having ribs on a face thereof, the crest faces of said ribs having a surface coating, extending to a slight depth into depth with a substance and the portion the pores of the wood, of metallic lead and anfaces of said ribs being imbeing free of said 

